Valid values are stable, beta, and unstable. If unspecified, the stable
channel will be used.

Shims and Command Line Flags

This buildpack installs shims that always add --disable-gpu
and --no-sandbox to any google-chrome command as you'll have trouble
running Chrome on a Heroku dyno otherwise.

You'll have two of these shims on your path: google-chrome and
google-chrome-$GOOGLE_CHROME_CHANNEL. They both point to the binary of
the selected channel.

Selenium

To use Selenium with this buildpack, you'll also need Chrome's webdriver.
This buildpack does not install chromedriver, but there is a
chromedriver buildpack
also available.

Additionally, chromedriver expects Chrome to be installed at /usr/bin/google-chrome,
but that's a read-only filesystem in a Heroku slug. You'll need to tell Selenium/chromedriver
that the chrome binary is at /app/.apt/usr/bin/google-chrome instead.

To make that easier, this buildpack makes $GOOGLE_CHROME_BIN, and
$GOOGLE_CHROME_SHIM available as environment variables. With them, you can
use the standard location locally and the custom location on Heroku. An example
configuration for Ruby's Capybara: